Newly developed material can suppress thermal runaway in batteries

A team of engineers and materials scientists from LG Chem, Korea’s largest chemical company, has developed a material they say could significantly reduce the risk of thermal runaway and fires in batteries. In their article published in the journal Natural communicationsthe group describes how they developed the hardware and how it performed in testing.

Over the past few years, consumers have witnessed or heard about smartphone batteries or cars catching fire. These fires have been found to result from thermal runaway, which is when the anode and cathode inside a battery come too close or, even worse, touch.

The result is a short circuit, which generates heat, and which shortly afterwards results in a fire. In this new effort, the LG team developed a thin material that, when placed between the cathode and collector, prevents thermal runaway.

The idea behind this new material is to stop the flow of electricity inside the battery if it starts to overheat. Adding electronic sensors would be too bulky and could suffer a heat failure before cutting off the electrical flow.

A better idea, the research team suggests, is to place a thin piece of conductive material between the anode and the collector, through which current flows into the battery – a piece that automatically stops being conductive at a certain temperature.

The new material is a metal composite that the LG team calls the Security Reinforcement Layer (SRL). They made a tiny sheet of material just a micrometer thick and placed it in a traditional battery, then tested its functionality.

They found that beyond normal conditions, where temperatures varied between 90°C and 130°C, the SRL served as a conductor, allowing current to flow normally. But as temperatures increased, the resistance increased by 5,000 ohms per degree C, leading to a reduction in current. The team also found that the opposite was true: As temperatures decreased, strength decreased.

The researchers also tested their improved battery in real-world conditions. In one such test, they hammered a nail into it, a move that almost always causes batteries to catch fire, and found that with the SRL in place, either no fire occurred or a small fire did start. and turned off automatically very quickly. The team also tried crushing the battery with a heavy weight, another surefire way to ignite a battery, and got the same results.

The team plans to continue testing the safety of SRLs in different battery sizes and types with the goal of selling them to battery manufacturers in the near future.

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